Lightweight portable postal scales serve a useful function for postal patrons who do not have access in their home or work areas to more complicated platform scales available at post offices and elsewhere. In particular, a portable postal scale enables the user to determine whether the weight of a letter exceeds a maximum amount such as one ounce.
All of the prior art presents various limitations and disadvantages. Many of the devices in the prior art have multiple components that make the accuracy of a scale more difficult to achieve in the manufacturing process. Other devices require coins to balance beams; coins have varying weight tolerances themselves that again affect the accuracy of a scale. Devices that require placement of a letter horizontally at a predetermined location on a beam introduce inaccuracy to the weighting function because of variances in the center of gravity from one letter to another with equal outside dimensions and even the same total weights. Still other devices require letters being weighed to be hung over the side of a desk or other work surface. During the weighing function, these devices can fall from the desk damaging the letter or the device and making repeated weighing trials awkward. A disadvantage of other balance beam type of scales is that they do not maintain weighing accuracy when used on surfaces that are unlevel.
The present invention is provided to overcome these limitations and disadvantages.